The present invention relates generally to pumping production fluids from a well, and particularly to a system and method that facilitates the pumping of production fluids having a high gas to liquid ratio.
In producing petroleum and other useful fluids from production wells, it is generally known to provide a pumping system for raising the fluids collected in a well. Production fluids enter a wellbore via perforations formed in a well casing adjacent a production formation. Fluids contained in the formation collect in the wellbore and may be raised by the pumping system to a collection point.
In an exemplary pumping system, such as a submergible pumping system, the system includes several components. For example, a submergible electric motor is used to power a submergible pump, typically a centrifugal pump.
The pumping system is deployed within the wellbore by a deployment system, such as production tubing, through which the production fluids are pumped to the earth""s surface. It is also common practice to set a packer within the wellbore casing. The packer is disposed between the wellbore casing and the deployment system or pumping system components.
In certain wells, such as in many offshore oil wells, deep set packers are used to protect the wellbore casing. During production, such wells can produce free gas that accumulates beneath the packer. The gas pocket can continue to grow during pumping. If the gas pocket becomes sufficiently large, it can reach the pump intake and cause slugging to occur in the electric submergible pumping system. To avoid this problem, well operators can maintain a bottom hole pressure above the bubble point of the produced fluid. However, the higher bottom hole pressure reduces the rate of production at these wells.
Attempts have been made to remove the gas, while maintaining higher production rates. For example, coil tubing can be used to vent the gas from beneath the packer to the surface. However, such methods substantially complicate the completion, e.g. electric submergible pumping system.
A system is provided for producing production fluids from a wellbore. The system is comprised of an electric submergible pumping system that includes at least one submergible pump, at least one pressure reduction device, at least one intake disposed to draw liquid, and at least one secondary intake coupled to the at least one pressure reduction device. The at least one pressure reduction device is powered by the at least one submergible pump and draws a gas from the wellbore through the at least one secondary intake.
According to another aspect of the invention, a system is provided for removing free gas from a wellbore. The system is comprised of: a submergible pump; a pressure reduction device through which the submergible pump forces a flow of wellbore fluid; a gas inlet coupled to the pressure reduction device and disposed within the wellbore at a gas pocket formation region; and source of power for the pump.
According to another aspect of the invention, a method is provided of producing fluids and removing free gas from a wellbore. The method is comprised of locating a submergible pump in a wellbore and powering the submergible pump with a submergible motor. The method further includes discharging wellbore fluid flow from the submergible pump through a pressure reduction device to create a low pressure area. The method further includes coupling the low pressure area with a gas formation area disposed in the wellbore.